An L+1 group is an L group with a leg. The leg can be at the short side or the long side of the L shape. In both cases the group lives or dies according to who has sente.
The first L+1 group lives or dies according to who has sente.
Black can live by playing on the 1-2 point as shown.
White can kill by playing hane at . This reduces the shape to the standard L group, which we already know is dead.
The extra hane gives some degree of security.
The throw-in at no longer works:
jumps and lives. If
makes a placement,
connects, and White cannot connect at a due to shortage of liberties, otherwise Black captures three to make an eye.
However, White can kill by the hane at followed by the placement at
.
tries to live, but
forces
, so
makes a throw in and kills. Note the importance of the
stone.
If the leg is on the other side, again the position depends on who has sente.
Now the 2-2 point is the vital point for Black.
Again, reducing Black to a basic L group by a hane, kills the corner.
The hane at may give some help in living.
The throw-in at doesn't work anymore. Black lives with
: White can not connect at a because Black can capture three to make an eye.
To kill, can go straight to the 2-2 point. After
, Black is dead. See the addendum of the rectangular six in the corner page. As before, the
stone is important.
The extra hane gives some degree of security. The squared stone provides an outward escape.
The attachment at leads to ko.
The second L+1 group with a weak leg is also unsettled. White can kill at a or Black can live by playing at a.
See also: